Apparatus for the generation of short electrical waves



April 9, 1929. V VON ARCQ 1,708,530

APPARATUS FOR THE GENERATION OF SHORT ELECTRICAL WAVES Filed July 15, 1925 awuemtoz Geozg 1612 (7'00,

hi lbtom Patented Apr. 9, 19.29.

LOSE TELEGRAPHLE I M. B. H PGRAT QIT 8F GERMANY.

APPARATUS THE Application filed July 15, 1925,.5cria1 llo.

may be produced by subjecting thechargesupplied from a high tension direct current source to the control of a rapidlyrunning interrupter. Gf course, this, method will prove unsuccessful in cases in which frequencies are used of such a high value as have of late come into practice for the purpose of bridging very great distances in radio work, i. e., ranging up to 1O-30 million oscillations per second.

According to this invention, iron core coils are used for the object of interrupting the supply current whereby very high m0dulated or chopped waves are obtained.

Iron containing coils have become known in high frequency equipments for the purpose of control under the name of chopper or modulator chokes or coils. By the'variation of a direct current auxiliary magnetization, the inductance andconsequently the alternating current resistance of the coils is varied, and in this regard they behave just like modulator coils.

Measurements have shown that these coils vary in their behavior if the frequency becomes very high. On account of the higher losses in the iron, within therange of frequencies here under consideration, they do not behave like variable self inductances, but like variable ohmic resistances. lit is comparatively easy to make coils which vary their resistance at the ratio of 1: 20 or even as 1: 30 if they are provided with auxiliary direct current magnetization.

Now, this characteristic is used in the present invention where the coil is inserted as an interrupter between the oscillatory circuit and thehigh tension source.

In the diagrammatic drawing herewith forming part of the'specification, a form of construction is shown by way of example embodying this feature. ais the oscillatory circuit which is fed with direct current by way of the terminals Z); c is the modulator coil whose auxiliary magnetizing windingd, is supplied by oscillator 6 with a current of high frequency, instead of with direct current or low frequency alternating current. This current may be generated, for instance, by means of a separate tube generator. The

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13,?71, and in Germany July 25, 1924.

either-for eachoscillation of the high frequency working circuit a or whole multiple thereof, a charge impulse supplied.

, in an arrangement of this sort, the shape of the voltage curve of the current with which the 'modulator coil is magnetized, is of utmostimportance." The current curve must be of such a form that the magnetizing curve attains its crest value as rapidly as feasible, that it preserves this value for a short while, and that it is thereupon caused to. drop as steeply as possible. Until the next rise takes place, there should be a time interval three times as long during which the working circuit goes through oscillation. In order to produce a magnetizing current of such a nature, because of the great oscillation constancy required, the most convenient plan is to use a cathode tube generator in which, by the adoption of suitable means, for instance, by the aid of iron core coils, such a distortion as stated is obtained in the current or the voltage curve. t is only if this magnetization is made to operate with absolute uniformity and regularity that a constant current amplitude is realized in the high frequency circuit. The magnetization therefore, is at the same time a measure and criterion of the coin stancy and regularity of the exciter. Instead of providing a charge impulse for each whole oscillation of the worki cirh cult, it may be sufiicient to give a charge impulse for every two, three, or more whole oscillations of the working circuit, similarly as done lnshock-excitation. In other words, the excitation is 1n rhythm with the oscillation circuit. Until the next energy supply occurs, the amplitude of the working circuit falls off.

Instead of using a cathode tube for the control of the choke it would also be possible, at least for the case where a new charge impulse is to be produced for each oscillation of the high frequency circuit, to take the control energy also from the high frequency circuit itself. In this case it must, of course, be kept in mind that, apart from the proper voltage and current curve, the

position of the phase of the magnetizing current must be in the proper relationship to a the high circuit.-

That I claim and desire to protect by Letters Patent is:

1. In an apparatus for producing short electrical waves an oscillation circuit supplied With energy from a high tension direct current source and an iron core choke coil in series With said circuit and excited at a predetermined high frequency differing from the frequency of the high. frequency current in the oscillation circuit.

2. In an apparatus for producing short electrical Waves, a high frequency oscillation circuit supplied With energy from a hi gh tension source and an iron core choke coil excited by a high frequency current having a predetermined frequency and phase With respect thereto the excitation frequency differing from that of the resonant frequency of the oscillation circuit.

8. In apparatus for generating high frequency electrical oscillations an oscillation circuit a high tension direct current source and an iron cored choke coil in series, and a high frequency oscillator exciting said choke coil at a frequency equal to a fraction of the resonant frequency of said oscillation circuit.

4. In apparatus for shock exciting a tuned high frequency oscillation circuit, a higl'i tension direct current source supplying energy to said circuit through an iron cored choke coil, and a high frequency oscillator energizing said choke at a frequency equal to a fraction of the resonant frequency of the tuned circuit.

Signed at Berlin Germany, this 27th day of June, 1925.

GEORG VON ARGO. 

